A known grille apparatus for a vehicle configured with plural cover members (elongated plates for the grille apparatus) arranged at an opening portion of a front grille of a vehicle to change an opening amount of the front grille by rotating the cover members is disclosed in JPS58-139519U (hereinafter referred to as Patent reference 1).
That is, for example, when a vehicle runs at a high speed, an aerodynamic performance (for example, Cd value, that is, coefficient of drag) of the vehicle is enhanced by limiting a flow rate of air flowing into an engine room by reducing an opening amount of a front grille (closed state). When starting an engine, warm-up time is shortened by reducing the flow rate of air introduced into a radiator of the vehicle. When an engine temperature has increasing tendency, the opening amount of the front grille is increased to raise the flow rate of air flowing into the engine room (open state) so that the engine temperature is controlled at an appropriate temperature.
However, in these years, shapes of cover members arranged at an opening portion of a front grille tend to be three dimensional including a three-dimensional curved surface in terms of designability. Therefore, opening and closing operations in response to the rotational movement of the aforementioned cover members disclosed in Patent reference 1 may not be able to change the opening amount of the front grille sufficiently.
Another grille apparatus is disclosed in 2012-148705A (hereinafter referred to as Patent reference 2). The grille apparatus disclosed in Patent reference 2 is configured with a second cover member performing opening and closing operations between a closed position to close an opening portion of a front grille and an open position to open the opening portion of the front grille.
That is, the second cover member is arranged at the position where frontward of first cover members is covered and moves to a position where the frontward of the first cover members is exposed. Then, an opening amount of the front grille may be changed, or varied reliably regardless of shapes of the cover members.
However, according to Patent reference 2, because a stroke of the second cover member for the opening and closing operations, that is, a moving distance of the second cover member, is increased, the grille apparatus disclosed in Patent reference 2 requires not only time to open and close the opening portion of the front grille but also a large space for arranging a housing portion for the second cover member and for arranging a movement mechanism that moves the second cover member. Thus, the mountability is decreased.
A need thus exists for a grille apparatus for a vehicle which is not susceptible to the drawback mentioned above.